In Agile methodologies, a Product Owner is a person who understands and has the vision for the software being developed. His / her role is to provide leadership and be a bridge between the user community and the Agile team. The Product Owner must be able to convey the vision of the product to the Agile team. Here are the key roles and responsibilities of a Product Owner:

1. Provides leadership across organization and is an empowered individual
2. Understands the product and provides vision
3. Owns the business case and Return On Investment
4. Facilitates requirements modeling sessions, including requirements envisioning and business analysis
5. Educates team in the business domain
6. Prioritizes the requirements, defects, and other work items for the Agile team
7. Actively participates in Agile meetings
8. Helps the team gain access to expert stakeholders
9. Participates in user acceptance testing
10. Keeps the project aligned with the organization’s direction, strategies and funding resources
11. Provides factors that may affect the Agile project – Enterprise Environmental Factors
12. Provides organizational policies, strategies and project objectives – Organizational Process Assets
13. Provides timely information and decisions
14. Announces releases and communicates Agile project status to the user community and the organization

The above mentioned roles and responsibilities clearly identify that a Product Owner plays a pivotal role in the success of an Agile project. Although the product owner prioritizes the product backlog, during the sprint / iteration planning meeting the Agile team selects the amount of work they believe they can do during each sprint / iteration. The Agile team decides how many sprints / iterations will be required for the project. An Agile team members know best what they are capable of and so they select which user stories from the prioritized product backlog they can commit to delivering during a sprint / iteration.

Requirements leading to product backlog are allowed to change (and change is encouraged) but only outside the sprint / iteration. Once the Agile team starts on a sprint / iteration it remains focused on backlog of that sprint / iteration.